- Synthesis of new 7-amino-3,4-dihydroquinolin-2(1H)-one-peptide derivatives and their carbonic anhydrase enzyme inhibition, antioxidant, and cytotoxic activities
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Six new monopeptides, seven new dipeptides, and two deprotected monopeptide dihydroquinolinone conjugates were prepared by the benzothiazole-mediated method and their structures were confirmed by nuclear magnetic resonance, mass, infrared spectroscopy, and elemental analysis methods. The human carbonic anhydrase (hCA) I and hCA II enzyme inhibition activities of the compounds were determined using the stopped-flow instrument. The synthesized peptide–dihydroquinolinone conjugates 2, 3, 6, 10, 13, and 15 showed inhibition against the hCA II enzyme in the range of 15.7–65.7 μM. However, none of the compounds showed inhibition of hCA I at a concentration of 100 μM. The antioxidant activities of the compounds were also examined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method at concentrations of 12.5–125 μg/ml, but when compared with the standard antioxidant compounds α-tocopherol and butylated hydroxyanisole (BHA), weak antioxidant activities were detected. The cytotoxic effects of four compounds against the A549 and BEAS-2B cell lines were also investigated. Among the compounds studied, compound 7 was found to be most effective, with the IC50 values on the A549 cells for 48 and 72 h being 26.87 and 9.979 μg/ml, respectively, and the IC50 values on the BEAS-2B cells being >100 μg/ml. None of the tested compounds showed antimicrobial activity in the concentration range (800–1.56 μg/ml) studied.
- Kü?ükbay, Hasan,G?nül, Zeynep,Kü?ükbay, Fatümetüzzehra Zehra,Tekin, Zehra,Angeli, Andrea,Bartolucci, Gianluca,Supuran, Claudiu T.,Tatl?c?, Eray,Apohan, Elif,Ye?ilada, ?zfer
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- Non-phosgene route to unsymmetrical ureas from N-Cbz-α-amino acid amides
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A convenient method toward the synthesis of α-amino acid-derived unsymmetrical ureas 2 is described herein. This route involves an interesting rearrangement of amides of N-Cbz-α-amino acids 1, which presumably entails the intermediacy of hydantoins that is followed by hydrolysis to afford unsymmetrical ureas 2 in quantitative yields and high purity.
- Ghazvini Zadeh, Ebrahim H.,Abo-Dya, Nader E.,Sotuyo, Ania C.,Ghiviriga, Ion,Hall, C. Dennis
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p. 5467 - 5469
(2013/09/23)
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- Green, catalyst-free synthesis of mesalazine conjugates
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A greener protocol for the synthesis of mesalazine conjugates is reported. Mesalazine conjugates are prepared in high yields by a one-pot reaction of mesalazine and aminoacyl/peptidoylbenzotriazoles in water under microwave irradiation. Georg Thieme Verlag Stuttgart New York.
- Ibrahim, Mohamed A.,Panda, Siva S.,Alamry, Khalid A.,Katritzky, Alan R.
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p. 3255 - 3258
(2013/12/04)
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- Chemical ligation of S-scylated cysteine peptides to form native peptides via 5-, 11-, and 14-membered cyclic transition states
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Cysteine-containing dipeptides 3a-l, (3b+3b′) (compound numbers in parentheses are used to indicate racemic mixtures; thus (3b+3b′) is the racemate of 3b and 3b′), and tripeptide 13 were synthesized in 68-96% yields by acylation of cysteine with N-(Pg-α-aminoacyl)- and N-(Pg-α-dipeptidoyl)benzotriazoles (where Pg stands for protecting group in the nomenclature for peptides throughout the paper) in the presence of Et3N. Cysteine-containing peptides 3a-l and 13 were S-acylated to give S-(Pg-α-aminoacyl)dipeptides 5a-l and S-(Pg-α-aminoacyl) tripeptide 14 without racemization in 47-90% yields using N-(Pg-α- aminoacyl)benzotriazoles 2 in CH3CN-H2O (7:3) in the presence of KHCO3. (In our peptide nomenclature, the prefixes di-, tri-, etc. refer to the number of amino acid residues in the main peptide chain; amino acid residues attached to sulfur are designated as S-acyl peptides. Thus we avoid use of the prefix "iso".) Selective S-acylations of serine peptide 3k and threonine peptide 3l containing free OH groups were thus achieved in 58% and 72% yield, respectively. S-(Pg-α-aminoacyl)cysteines 4a,b underwent native chemical ligations to form native dipeptides 3f,i via 5-membered cyclic transition states. Microwave irradiation of S-(Pg-α-aminoacyl)tripeptide 15 and S-(Pg-α-aminoacyl)tetrapeptide 17 in the presence of NaH2PO4/Na2HPO 4 buffer solution at pH 7.8 achieved chemical ligations, involving intramolecular migrations of acyl groups, via 11- and 14-membered cyclic transition states from the S-atom of a cysteine residue to a peptide terminal amino group to form native peptides 19 and 20 in isolated yields of 26% and 23%, respectively.
- Katritzky, Alan R.,Tala, Srinivasa R.,Abo-Dya, Nader E.,Ibrahim, Tarek S.,El-Feky, Said A.,Gyanda, Kapil,Pandya, Keyur M.
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experimental part
p. 85 - 96
(2011/04/12)
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- Convenient synthesis of C-terminal di- and tri-peptide amides from N-protected dipeptidoylbenzotriazoles
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N-Protected dipeptidoylbenzotriazoles react with aqueous ammonia to give dipeptide primary amides (77-98%) and with N-unprotected α-amino amides to afford tripeptide primary amides (82-86%).
- Celik, Ilhami,Abdel-Fattah, Ashraf A.A.
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experimental part
p. 4923 - 4929
(2009/10/09)
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- Preparation of polyfunctional acyl azides
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(Chemical Equation Presented) A general synthesis of acyl azides from the corresponding N-acyl benzotriazoles is described. The procedure affords acyl azides in good yields and avoids the use of acid activators and NO+ equivalents typically emp
- Katritzky, Alan R.,Widyan, Khalid,Kirichenko, Kostyantyn
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p. 5802 - 5804
(2008/02/09)
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- The efficient preparation of di- and tripeptides by coupling N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles with unprotected amino acids
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N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles 2 and N-protected peptidoylbenzotriazoles 6 are coupled in aqueous acetonitrile solution with free amino acids or dipeptides to prepare: (i) 22 chirally pure dipeptides 5a-v (in an average yield of 82%) from N-(Cbz- or Fmoc-α-aminoacyl)benzotriazoles 2 and unprotected amino acids, (ii) five chiral tripeptides 7a-e (in an average yield of 75%) from N-protected peptidoylbenzotriazoles 6 and unprotected amino acids, (iii) one chiral tripeptide 7g (62%) from N-(Cbz- or Fmoc-α- aminoacyl)benzotriazole 2a and the free dipeptide 8. In all, N-(Cbz- or Fmoc-α-aminoacyl)benzotriazole derivatives of 17 of the 20 naturally occurring amino acids were used, including those containing the following unprotected side chain functionalities: alcoholic -OH (Ser), indole -NH (Trp), imidazole -NH, phenolic -OH (Tyr), -CONH2 (Gln, Asn), -SH (Cys), -CO2H (Glu, Asp), and -S-S (Cystine). Support for the complete retention of chirality was obtained by parallel experiments involving D-Ala, L-Ala, and DL-Ala for the preparation of di- and tripeptides. This and other evidence for chiral integrity was supported by NMR and HPLC analyses. Georg Thieme Verlag Stuttgart.
- Katritzky, Alan R.,Angrish, Parul,Suzuki, Kazuyuki
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p. 411 - 424
(2007/10/03)
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- N-(Cbz- and Fmoc-α-aminoacyl)benzotriazoles: Stable derivatives enabling peptide coupling of Tyr, Trp, Cys, Met, and Gln with free amino acids in aqueous media with complete retention of chirality
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Crystalline, chirally stable N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles 2a-f, activated derivatives of Tyr, Trp, Cys, Met and Gln undergo peptide coupling in aqueous media with unprotected L-Ala-OH and L-Phe-OH to give the chiral dipeptides in 70-98% yi
- Katritzky, Alan R.,Angrish, Parul,Huer, Deniz,Suzuki, Kazuyuki
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p. 397 - 402
(2007/10/03)
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